35mm 1.4G

Why the big discrepancy in price on f/1.4 lenses?

I love using big f stop lenses. My favorite was a was an old f 1.4 57mm Konica. Now I'm thinking of buying an f1.4 for my Sony DSLR. With the full frame Sony DSLR coming out latter this year it seems like the 50mm would be a good choice. Sony offers three focal lengths for f/1.4, 35mm, 50mm, and the CZ 85mm. I don't understand why 35mm and 85mm offering by Sony are priced four times as expensive as the 50mm. I must be missing something. Are the others so much better or is it something else?